肺炎链球菌SPD_1713蛋白与tRNAPhe结合机制研究

肺炎链球菌是威胁人类健康的重要病原体，随着其耐药性的提升，探究新的抗菌策略成为研究热点。我们前期合成了一种能特异性识别细菌苯丙氨酰tRNA合成酶（tRNAPhe合成酶）的靶向抑制剂-ptsc1，可明显抑制肺炎链球菌的生长，定量蛋白组学分析显示该抑制剂处理组中的新蛋白SPD_1713显著高表达。在本项目中，我们运用生物信息学分析发现该蛋白含有结合tRNAPhe的功能域，分子对接结果预测到tRNAPhe的结合位点，进一步的酶活性检测结果初步显示SPD_1713具有tRNAPhe合成酶的活性。基于这些前期结果，我们推测SPD_1713为潜在的tRNAPhe合成酶。本项目以SPD_1713为切入点，综合利用生物信息学分析、蛋白结构解析、分子生物学和生化表征等技术深入研究SPD_1713与tRNAPhe结合的热力学和动力学特征，从而揭示二者结合的分子机制，为治疗肺炎链球菌引起的疾病提供多元化思路。

Streptococcus pneumoniae (S. pneumoniae) is an important pathogen threatening human health. With the development of drug resistance, it has become a research highlight to explore new antibacterial strategies. We have previously synthesized an inhibitor ptsc1 that can specifically recognize bacterial phenylalanyl-tRNA synthetase (tRNAPhe-synthetase) and thus inhibit the growth of S. pneumoniae. Quantitative proteomic analysis showed that a novel protein SPD_1713 was highly expressed in ptsc1 treatment group. In the current study, bioinformatics analysis indicated that SPD_1713 contained the binding domain of tRNAPhe, and the key residues in the tRNAPhe-binding site were successfully predicted by molecular docking. Subsequent enzymatic activity assay showed that SPD_1713 possesses tRNAPhe-synthetase activity. Based on these previous results, we speculated that SPD_1713 was a potential tRNAPhe-synthetase. Overall, we will investigate thermodynamic and kinetic characteristics of the binding of SPD_1713 and tRNAPhe by bioinformatics analysis, protein structure analysis, molecular biological and biochemical characterization to revel the molecular mechanism of SPD_1713 and tRNAPhe. This study will provide new insights for the treatment of diseases caused by S. pneumoniae.